Pneumatic horn



Patented May 273, `1939` i UNITED STATES PATENT OFFICE l PNEUMATIC HORN Cecil S. Kelley, Forest Hills, Pa., assignor to Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania,

Application November 3, 1936, Serial No. 108,924

3 Claims.

This invention relates to sound producing devices, and more particularly to the type employing a vibratory element.

In designing sound producers of the above type i it p has heretofore been proposed to employ vibra- I which elements are secured in their operating podifferential pressures.` Diiiiculty may be experiable vibratory element operable by a partial vacuum and so arranged as to dispense with springs or other biasing means.

sitions by suitable means and are adapted to vibrate for producing sounds when subjected to enced in operation of such sound producers due to breakage of the diaphragms or the biasing springs, and in addition the resistance to movement of the vibratory elements may be such as to render operation of the sound producers 'by partial vacuum impracticable.

The principal object of my invention is to provide an improved sound producer` of rugged and inexpensive construction, which has a freely mov- In the accompanying drawing, Fig. 1 is a view, mainly in section, of a sound producing device constructed according to my invention; and Fig. 2 is a plan View of one of the vibratory disk Valves shown in Fig. 1. p

Referring to the drawing, the sound producing device shown is of the dual type, comprising two similar units arranged side by side and adapted to be operated to produce a double note, although it will be understood that myinvention may be embodied in a device consisting of one or any number of units as desired.

shown in the drawing,lthe`sound producing w is provided with an end portion 8, which is in sealing engagement with an annular shoulder 9 `formed within the body Vcasing adjacent a chamber 'I0 that is open to atmosphere through the as- Vsecured the ends of horns 4 and 4.

`bers 6, each of which has screw threaded connection in one of a pair of suitable bores formed in the body casing in alignment with the respectivehorns 4 and 4.

Eachseat member 6 is cylindrical in form and sociated horn. 'Ihe end portion 8 of each seat `member 6 has formed thereon an inverted annu- `ilopens into the chamber I0.

` lar seat rib II surrounding an aperture I2 which bers I0 and bores I2 is quickly restored to that A pair of adjustable hollow elements I4 are mounted in and have screw-threaded engagement with the seat members 6, each of said elements having formed on one end thereof an an- A n-ular seat rib I5, which surrounds a central bore `5 I6 in the element and is adapted to be aligned with the inverted seat rib I I on the associated seat member 6.

Interposed between the seat ribs I5 and II in each unit of the sound producing device is a disk valve Il, which has several circumferentially spaced guide lugs I8 formed thereon and which slidably engages the wall of an annular chamber I9 surrounding the seat ribs I5 andfII in each of the seat members 6. Each of the "chambers I9 is connected to a pipe 24 by Way of apertures 2l formed in the respective members 6, annular grooves 22 formed in the body casing I, and passages 23. The pipe 24 is `adapted to be connected, when it is desired to operate the sound producing device, to a suitable partial vacuum source.

The distance lbetween the aligned seat ribs I I and I5 is greater than the thickness of the valve disks II, which are adapted to be alternately impinged into seating engagement with said ribs to produce sounds in the manner hereinafter explained. The tonal quality of the sounds produced is determined in part by the distances between the seat ribs, which may be varied as desired by adjustment of the screw-threaded elements I4 within the members 6. Lock nuts 25 are provided on the respective elements I4 and are adapted to be turned into engagement with the outer ends of the seat members 6 for locking the elements I4 in their adjusted positions.

In operation, assuming that the vvalve disks I'I are initially in seating engagement with the seat ribs i5 as shown in the drawing, when a partial vacuum is created in the pipe 24, air is withdrawn from the chamber I0 and aperture I2 adjacent each valve disk by iiow past the seat rib II and through the annular chamber I 9, apertures 2l, groove 22 and passage 23 at such a rate as to eifect a rapid reduction in the uid pressure acting on the right-hand face of each valve disk. The atmospheric pressure of air in each of the bores I6 is then suiiicient to move the I adjacent valve disk Il away from the seat rib of the atmosphere, while the fluid pressure in the bores I6 is reduced by suction of air through the chambers I9, and passages 2|, 22 and 23 and pipe 24. The atmospheric pressure acting through apertures I2 on the valve disks I'i is then sufcient to move said valve disks into engagement with the seat ribs I5.

The operation of the valve disks just described is rapidly repeated. as: long asV a partial vacuum is maintained in the pipe 24, and the resultant Vibrations of the disks and the surrounding air produce sounds which are amplied in the usual manner by the horns 4. i

It will be apparent that the sound producing device comprises relatively few parts and is thus capable of being manufactured at minimum cost, and that the freely movable and unbiased vibratory element provided in the device is adapted to resist possible breakage in operation.

While one illustrative embodiment of the inventionhas been described in detail, it is not my 4intention to limit its scope to that embodiment or otherwise than by lthe vterms of the appended claims.

` Having now described my invention, what I claim as new and ldesire tc secure by Letters Patent, is:

1. A sound producing device comprising a body, a seatmember removably mounted in said body and having an annular seat rib surrounding an 2. A sound producing device comprising a body, a seat member removably mounted in said body and having an inverted annular seat rib surrounding an atmospheric opening, an adjustable member having screw-threaded connection in said seat member, an annular seat rib surrounding an atmospheric opening in said adjustable member and adapted to be spaced from and aligned with the first-named seat rib, a chamber surrounding said seat ribs and connected to means for creating a-partial vacuum therein, a vibratory disk valve of a thickness less than the distance between said seat ribs and interposed therebetween, said disk valve being operative upon the creation of a partial vacuum in said chamber to engage said seat ribs alternately for opening and closing communication between said chamber and the atmosphere through each of said atmospheric openings in succession, and means for amplifying the sound thereby produced by vibration of said disk valve.

3. A sound producing device comprising a body, a seat member removably mounted in said body and having an inverted annular seat rib surrounding an atmospheric opening, an adjustable member having screw-threaded connection in said seat member, anannular seat rib surround* ing an atmospheric opening in said ladjustable member and adapted to be spaced from and aligned with the rst-named seat rib, a chamber surrounding said seat ribs and connected to means for creating a partial vacuum therein, and

a disk valve interposed between said seat ribs and having a plurality of spaced lugs on the periphery thereof in sliding engagement with the Wall of said chamber, said disk valve being freely movable into and out of seating engagement with said seat ribs in succession upon the creation of a partial vacuum in said chamber.

CECIL S. KELLEY. 

